Executive Privilege

power claimed by the US President and other members of the Executive Branch to resist certain Search Warrant-s and other encroachments. The concept of executive privilege is not mentioned in the US Constitution.

Historically, the usage of executive privilege underscores the untested nature of the doctrine, since Presidents have generally sidestepped open confrontations with Congress and the courts over the issue by first asserting the privilege, then producing some of the documents requested on an assertedly voluntary basis.

In 1998, President Bill Clinton became the first President since Nixon to assert executive privilege and lose in court, when a Federal judge ruled Clinton aides could be called to testify in the Monica Lewinsky scandal.

President George W Bush invoked executive privilege "in substance" in refusing to disclose the details of Vice President Dick Cheney's meetings with Energy Industry executives. In 2004, the US Supreme Court upheld Bush's action.

http://en.wikipedia.org/wiki/Executive_privilege